From: Jason Gunthorpe <jgg@ziepe.ca> To: Arnd Bergmann <arnd@arndb.de> Cc: Nicolas Pitre <nico@fluxnic.net>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Masahiro Yamada <masahiroy@kernel.org>, Andrzej Hajda <a.hajda@samsung.com>, Neil Armstrong <narmstrong@baylibre.com>, Laurent Pinchart <Laurent.pinchart@ideasonboard.com>, Jonas Karlman <jonas@kwiboo.se>, Jernej Skrabec <jernej.skrabec@siol.net>, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>, Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>, "David S. Miller" <davem@davemloft.net>, Saeed Mahameed <saeedm@mellanox.com>, Leon Romanovsky <leon@kernel.org>, dri-devel <dri-devel@lists.freedesktop.org>, Linux-Renesas <linux-renesas-soc@vger.kernel.org>, Networking <netdev@vger.kernel.org>, linux-rdma <linux-rdma@vger.kernel.org> Subject: Re: [RFC 0/6] Regressions for "imply" behavior change Date: Wed, 8 Apr 2020 19:42:24 -0300 [thread overview] Message-ID: <20200408224224.GD11886@ziepe.ca> (raw) In-Reply-To: <CAK8P3a2frDf4BzEpEF0uwPTV2dv6Jve+6N97z1sSuSBUAPJquA@mail.gmail.com> On Wed, Apr 08, 2020 at 10:49:48PM +0200, Arnd Bergmann wrote: > On Wed, Apr 8, 2020 at 10:38 PM Nicolas Pitre <nico@fluxnic.net> wrote: > > On Wed, 8 Apr 2020, Arnd Bergmann wrote: > > > I have created workarounds for the Kconfig files, which now stop using > > > imply and do something else in each case. I don't know whether there was > > > a bug in the kconfig changes that has led to allowing configurations that > > > were not meant to be legal even with the new semantics, or if the Kconfig > > > files have simply become incorrect now and the tool works as expected. > > > > In most cases it is the code that has to be fixed. It typically does: > > > > if (IS_ENABLED(CONFIG_FOO)) > > foo_init(); > > > > Where it should rather do: > > > > if (IS_REACHABLE(CONFIG_FOO)) > > foo_init(); > > > > A couple of such patches have been produced and queued in their > > respective trees already. > > I try to use IS_REACHABLE() only as a last resort, as it tends to > confuse users when a subsystem is built as a module and already > loaded but something relying on that subsystem does not use it. > > In the six patches I made, I had to use IS_REACHABLE() once, > for the others I tended to use a Kconfig dependency like > > 'depends on FOO || FOO=n' It is unfortunate kconfig doesn't have a language feature for this idiom, as the above is confounding without a lot of kconfig knowledge > I did come up with the IS_REACHABLE() macro originally, but that > doesn't mean I think it's a good idea to use it liberally ;-) It would be nice to have some uniform policy here I also don't like the IS_REACHABLE solution, it makes this more complicated, not less.. Jason
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@ziepe.ca> To: Arnd Bergmann <arnd@arndb.de> Cc: Jernej Skrabec <jernej.skrabec@siol.net>, Leon Romanovsky <leon@kernel.org>, Neil Armstrong <narmstrong@baylibre.com>, David Airlie <airlied@linux.ie>, Networking <netdev@vger.kernel.org>, Masahiro Yamada <masahiroy@kernel.org>, Nicolas Pitre <nico@fluxnic.net>, Saeed Mahameed <saeedm@mellanox.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, dri-devel <dri-devel@lists.freedesktop.org>, Linux-Renesas <linux-renesas-soc@vger.kernel.org>, Andrzej Hajda <a.hajda@samsung.com>, Jonas Karlman <jonas@kwiboo.se>, Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>, Laurent Pinchart <Laurent.pinchart@ideasonboard.com>, "David S. Miller" <davem@davemloft.net>, linux-rdma <linux-rdma@vger.kernel.org> Subject: Re: [RFC 0/6] Regressions for "imply" behavior change Date: Wed, 8 Apr 2020 19:42:24 -0300 [thread overview] Message-ID: <20200408224224.GD11886@ziepe.ca> (raw) In-Reply-To: <CAK8P3a2frDf4BzEpEF0uwPTV2dv6Jve+6N97z1sSuSBUAPJquA@mail.gmail.com> On Wed, Apr 08, 2020 at 10:49:48PM +0200, Arnd Bergmann wrote: > On Wed, Apr 8, 2020 at 10:38 PM Nicolas Pitre <nico@fluxnic.net> wrote: > > On Wed, 8 Apr 2020, Arnd Bergmann wrote: > > > I have created workarounds for the Kconfig files, which now stop using > > > imply and do something else in each case. I don't know whether there was > > > a bug in the kconfig changes that has led to allowing configurations that > > > were not meant to be legal even with the new semantics, or if the Kconfig > > > files have simply become incorrect now and the tool works as expected. > > > > In most cases it is the code that has to be fixed. It typically does: > > > > if (IS_ENABLED(CONFIG_FOO)) > > foo_init(); > > > > Where it should rather do: > > > > if (IS_REACHABLE(CONFIG_FOO)) > > foo_init(); > > > > A couple of such patches have been produced and queued in their > > respective trees already. > > I try to use IS_REACHABLE() only as a last resort, as it tends to > confuse users when a subsystem is built as a module and already > loaded but something relying on that subsystem does not use it. > > In the six patches I made, I had to use IS_REACHABLE() once, > for the others I tended to use a Kconfig dependency like > > 'depends on FOO || FOO=n' It is unfortunate kconfig doesn't have a language feature for this idiom, as the above is confounding without a lot of kconfig knowledge > I did come up with the IS_REACHABLE() macro originally, but that > doesn't mean I think it's a good idea to use it liberally ;-) It would be nice to have some uniform policy here I also don't like the IS_REACHABLE solution, it makes this more complicated, not less.. Jason _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-04-08 22:42 UTC|newest] Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-04-08 20:27 [RFC 0/6] Regressions for "imply" behavior change Arnd Bergmann 2020-04-08 20:27 ` Arnd Bergmann 2020-04-08 20:27 ` [RFC 1/6] thunder: select PTP driver if possible Arnd Bergmann 2020-04-08 20:27 ` Arnd Bergmann 2020-04-08 20:27 ` [RFC 2/6] net/mlx5e: fix VXLAN dependency Arnd Bergmann 2020-04-08 20:27 ` Arnd Bergmann 2020-04-08 20:27 ` [RFC 3/6] LiquidIO VF: add dependency for PTP_1588_CLOCK Arnd Bergmann 2020-04-08 20:27 ` Arnd Bergmann 2020-04-08 21:10 ` kbuild test robot 2020-04-08 21:13 ` Arnd Bergmann 2020-04-08 20:27 ` [RFC 4/6] drm/bridge/sii8620: fix extcon dependency Arnd Bergmann 2020-04-08 20:27 ` Arnd Bergmann 2020-04-10 6:56 ` Andrzej Hajda 2020-04-10 6:56 ` Andrzej Hajda 2020-04-14 15:04 ` Arnd Bergmann 2020-04-14 15:04 ` Arnd Bergmann 2020-04-14 15:37 ` Daniel Vetter 2020-04-14 15:37 ` Daniel Vetter 2020-04-15 6:58 ` Jani Nikula 2020-04-15 6:58 ` Jani Nikula 2020-04-08 20:27 ` [RFC 5/6] drm/rcar-du: fix selection of CMM driver Arnd Bergmann 2020-04-08 20:27 ` Arnd Bergmann 2020-04-14 20:17 ` Laurent Pinchart 2020-04-14 20:17 ` Laurent Pinchart 2020-04-14 20:38 ` Arnd Bergmann 2020-04-14 20:38 ` Arnd Bergmann 2020-04-14 20:51 ` Laurent Pinchart 2020-04-14 20:51 ` Laurent Pinchart 2020-04-14 21:10 ` Arnd Bergmann 2020-04-14 21:10 ` Arnd Bergmann 2020-04-15 14:13 ` Geert Uytterhoeven 2020-04-15 14:13 ` Geert Uytterhoeven 2020-04-15 15:18 ` Arnd Bergmann 2020-04-15 15:18 ` Arnd Bergmann 2020-04-15 19:07 ` Arnd Bergmann 2020-04-15 19:07 ` Arnd Bergmann 2020-04-15 21:12 ` Laurent Pinchart 2020-04-15 21:12 ` Laurent Pinchart 2020-04-15 21:22 ` Arnd Bergmann 2020-04-15 21:22 ` Arnd Bergmann 2020-04-16 6:51 ` Daniel Vetter 2020-04-16 6:51 ` Daniel Vetter 2020-04-16 15:17 ` Laurent Pinchart 2020-04-16 15:17 ` Laurent Pinchart 2020-04-08 20:27 ` [RFC 6/6] drm/rcar-du: fix lvds dependency Arnd Bergmann 2020-04-08 20:27 ` Arnd Bergmann 2020-04-08 20:38 ` [RFC 0/6] Regressions for "imply" behavior change Nicolas Pitre 2020-04-08 20:38 ` Nicolas Pitre 2020-04-08 20:46 ` Saeed Mahameed 2020-04-08 20:46 ` Saeed Mahameed 2020-04-08 20:49 ` Arnd Bergmann 2020-04-08 20:49 ` Arnd Bergmann 2020-04-08 21:17 ` Nicolas Pitre 2020-04-08 21:17 ` Nicolas Pitre 2020-04-08 22:42 ` Jason Gunthorpe [this message] 2020-04-08 22:42 ` Jason Gunthorpe 2020-04-09 8:41 ` Jani Nikula 2020-04-09 8:41 ` Jani Nikula 2020-04-10 2:40 ` Saeed Mahameed 2020-04-10 2:40 ` Saeed Mahameed 2020-04-10 7:26 ` Geert Uytterhoeven 2020-04-10 7:26 ` Geert Uytterhoeven 2020-04-10 17:13 ` Jason Gunthorpe 2020-04-10 17:13 ` Jason Gunthorpe 2020-04-10 19:04 ` Saeed Mahameed 2020-04-10 19:04 ` Saeed Mahameed 2020-04-14 13:29 ` Jason Gunthorpe 2020-04-14 13:29 ` Jason Gunthorpe 2020-04-14 14:27 ` Arnd Bergmann 2020-04-14 14:27 ` Arnd Bergmann 2020-04-14 15:23 ` Jason Gunthorpe 2020-04-14 15:23 ` Jason Gunthorpe 2020-04-14 15:25 ` Arnd Bergmann 2020-04-14 15:25 ` Arnd Bergmann 2020-04-14 17:49 ` Saeed Mahameed 2020-04-14 17:49 ` Saeed Mahameed 2020-04-14 18:47 ` Arnd Bergmann 2020-04-14 18:47 ` Arnd Bergmann 2020-04-16 3:25 ` Saeed Mahameed 2020-04-16 3:25 ` Saeed Mahameed 2020-04-16 7:20 ` Arnd Bergmann 2020-04-16 7:20 ` Arnd Bergmann 2020-04-16 10:17 ` Jani Nikula 2020-04-16 10:17 ` Jani Nikula 2020-04-16 12:38 ` Arnd Bergmann 2020-04-16 12:38 ` Arnd Bergmann 2020-04-16 14:52 ` Jason Gunthorpe 2020-04-16 14:52 ` Jason Gunthorpe 2020-04-16 15:58 ` Arnd Bergmann 2020-04-16 15:58 ` Arnd Bergmann 2020-04-16 18:05 ` Jason Gunthorpe 2020-04-16 18:05 ` Jason Gunthorpe 2020-04-16 18:38 ` Saeed Mahameed 2020-04-16 18:38 ` Saeed Mahameed 2020-04-16 15:12 ` Nicolas Pitre 2020-04-16 15:12 ` Nicolas Pitre 2020-04-16 18:21 ` Jason Gunthorpe 2020-04-16 18:21 ` Jason Gunthorpe 2020-04-16 19:56 ` Andrzej Hajda 2020-04-16 19:56 ` Andrzej Hajda
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